Effect of continuous hemofiltration on hemodynamics, lung inflammation and pulmonary edema in a canine model of acute lung injury

Objective. This study examined whether continuous hemofiltration favorably affects cardiopulmonary variables, lung inflammation, and lung fluid balance in a canine model of oleic acid induced acute lung injury. Methods. Eleven pentobarbital-anesthetized dogs were randomly divided into a control (mechanical ventilation, MV) group (n=6) and a MV plus hemofiltration (HF) group (n=5). All animals received an intravenous injection of oleic acid (0.09 ml/kg) to induce acute lung injury. Continuous arterial-venous hemofiltration (blood flow 100 ml/min, ultrafiltration rate at 50-65 ml kg(-1) h(-1)) was started after establishment of oleic acid induced acute lung injury and continued for 4 h. Hemodynamics, lung mechanics, gas exchange, lung fluid balance, lung histology, and the level of plasma cytokines were assessed. Results. After 240 min of HF treatment there was a significant increase in cardiac output, reduction in pulmonary arterial pressure, and improvement in both oxygenation and lung mechanics. Also, in the HF group the lung wet-to-dry weight ratio was significantly reduced. Histologically, HF reduced edema and inflammatory cell infiltration in the lung. There was also a significantly greater decrease in plasma IL-6 and IL-8 levels in the HF group than in group receiving MV alone. Conclusions. In a canine model of acute lung injury continuous HF improved cardiopulmonary function, reduced pulmonary edema, decreased lung permeability and inflammation, and decreased the plasma concentration of proinflammatory cytokines.